In the 1983 decision Apple Computer, Inc. v. Franklin Computer Corp., 714 F.2d 1240 (3d Cir. 1983) an appellate level court in the United States held for the first time that a computer's operating system could be protected by copyright.
"Franklin Computer Corporation [Burlington, New Jersey] introduced the Franklin Ace 100, a clone of Apple Computer's Apple II, in 1982. Apple quickly determined that substantial portions of the Franklin ROM and operating system had been copied directly from Apple's versions, and on May 12, 1982, filed suit in the United States District Court for the Eastern District of Pennsylvania. It cited the presence of some of the same embedded strings, such as the name "James Huston" (an Apple programmer), and "Applesoft," on both the Apple and Franklin system disks.
"Franklin admitted that it had copied Apple's software but argued that it would have been impractical to independently write its own versions of the software and maintain compatibility, although it said it had written its own version of Apple's copy utility and was working on its own versions of other software. Franklin argued that because Apple's software existed only in machine-readable form, and not in printed form, and because some of the software did not contain copyright notices, it could be freely copied. The Apple II firmware was likened to a machine part whose form was dictated entirely by the requirements of compatibility (that is, an exact copy of Apple's ROM was the only part that would "fit" in an Apple-compatible computer and enable its intended function), and was therefore not copyrightable.
"The district court found in favor of Franklin. However, Apple appealed the ruling to the United States Court of Appeals for the Third Circuit which, in a separate case decided three days after Franklin won at the lower level, determined that both a program existing only in a written form unreadable to humans (e.g. object code) and one embedded on a ROM were protected by copyright. (See Williams Elec., Inc., v. Artic Int'l, Inc., 685 F.2d 870 (1982)). The Court of Appeals overturned the district court's ruling in Franklin by applying its holdings in Williams and going further to hold that operating systems were also copyrightable" (Wikipedia article on Apple Computer, Inc. v. Franklin Computer Corp., accessed 01-01-2013).